This invention is particularly applicable to blow-molded plastic containers used for dispensing a variety of different types of liquids, some of which may be toxic or flammable. As the container is tipped forwardly, the spout or neck portion will normally be lowered below the liquid level in the container, trapping the air in the container above the liquid. If a vent is not provided to admit air into this region, the flow of liquid out of the container creates a vacuum above the liquid remaining in the container. The vacuum increases with fluid leaving the container causing a contraction/expansion (glug, glug) action. The (glug, glug) action makes the poured stream of liquid leaving the pouring spout difficult to control, so the user may spill or otherwise improperly deposit the liquid. If the liquid is toxic or flammable the result can be catastrophic or life threatening and harmful to the environment. In the past, various attempts have been made to solve the contraction/expansion (glug, glug) problem. U.S. Pat. Nos. 3,251,514, 4,412,633, U.S. Pat. No. 4,804,119 and PCT International Publication No. WO86/02334 provide examples of how others have attempted to reduce or eliminate the contraction/expansion (glug, glug) effect.